error[E0435]: attempt to use a non-constant value in a constant --> $DIR/issue-27433.rs:5:23 | LL | const FOO : u32 = foo; | --------- ^^^ non-constant value | | | help: consider using `let` instead of `const`: `let FOO` error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0435`.